Malignant Tumors with Low FDG-PET Uptake: A case Report and Review of the Literature

Abstract

Background Fluorine 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a well-accepted examination for diagnosis, staging, and monitoring in clinical oncology.1 According to the higher glucose metabolism rate, malignant tumor cells have higher FDG uptake, besides higher FDG uptake is strictly correlated with poor prognosis in various types of cancer.2 However, FDG-PET has limitations associated with some of the cancer types that have low FDG uptake, even high metabolism.3 Low cellularity, low glucose metabolism, inadequate patient preparation, small-sized tumor, and cellular mucin might be cause to low FDG uptake.4 Low FDG uptake frequently presented in lepidic growth adenocarcinoma (formerly defined as bronchoalveolar adenocarcinoma), renal cell cancer, and mucinous neoplasms. Case Report We report on a case of 57-year-old female biopsy proven Signet Ring Cell Carcinoma (SRCC) patient without FDG-PET uptake in the evaluation for staging. The patient admitted to hospital with massive ascites and dyspeptic complaints. Further evaluation revealed the existence of SRCC with no FDG-PET uptake. Conclusion FDG-PET reveals valuably findings in clinical oncology for diagnosis, staging, and monitoring. Although FDG-PET uptake is correlated with most of the malignant tumors’ activity, some aggressive malignancies may have no/low FDG uptake and FDG uptake is not predictive of survival.

Keywords

• signet ring cell carcinoma
• srcc
• low fdg uptake
• low pet uptake
• mucinous carcinoma